A good understanding of the scaling up process and a framework for analysing scalability is critical for informed decision making. In this paper a six step process is proposed to assess the scalability of an intervention/project. The approach was used to assess the scalability of the electronic voucher systems of Zambia and the Super Seeds Project in Zimbabwe. Estimated scalability indexes for these two projects were 77 and 85 respectively indicating the high potential for scaling up. The numerical score should not be viewed as carrying mathematical precision, because the scoring is based on subjective assessments. Through a validation process it was established that the approach is logically consistent and technically sound .The methodology also allows for a careful and methodological diagnosis of constraints to scaling-up. Key requirements to perform this analysis are a good understanding of the scaling up process in the local setting: effective participation and engagement of the key stakeholders, and external facilitator with no vested interest in the outcome. However mechanical application of the approach or superficial comparison of scalability indexes of different projects is likely to result in misleading conclusions. The model should be tested more broadly to assess its robustness and wider applicability. Acknowledgement : This paper is based on a research project originally commissioned by Vuna, a regional Climate Smart Agriculture Programme (operating from 2015 - 2018), and funded by the British Government s Department for International Development (DFID) as part of the United Kingdom s aid programme. However, the views and recommendations contained in this report are those of the author, and DFID is not responsible for, or bound by the recommendations made.